International Mother Language Day (IMLD) is a worldwide annual observance held on 21 February to promote awareness of linguistic and cultural diversity and promote multilingualism. First announced by UNESCO on 17 November 1999, it was formally recognized by the United Nations General Assembly in a resolution establishing 2008 as the International Year of Languages.

International Mother Language Day has been observed annually since 2000 to promote peace and multilingualism around the world and to protect all mother languages. It is observed on February 21 to recognize the 1952 Bengali Language Movement in Bangladesh.

The day was proclaimed by the General Conference of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in November 1999 (30C/62). In its resolution A/RES/61/266, the United Nations General Assembly called on its member states "to promote the preservation and protection of all languages used by people of the world" on 16 May 2009. In the resolution, the General Assembly proclaimed 2008 as the International Year of Languages to promote unity in diversity and international understanding through multilingualism and multiculturalism. The resolution was suggested by Rafiqul Islam, a Bengali living in Vancouver, Canada. He wrote a letter to Kofi Annan on 9 January 1998 asking him to take a step to saving the world's languages from extinction by declaring an International Mother Language Day. Rafiq proposed the date as 21 February to commemorate the 1952 killings in Dhaka during the Language Movement.

Languages are the most powerful instruments of preserving and developing our tangible and intangible heritage. All moves to promote the dissemination of mother tongues will serve not only to encourage linguistic diversity and multilingual education but also to develop fuller awareness of linguistic and cultural traditions throughout the world and to inspire solidarity based on understanding, tolerance and dialogue.

/From the United Nations International Mother Language Day microsite/